1. Technical Field
The disclosure relates generally to the field of electronics devices, and networks thereof. More particularly, portions of the disclosure are directed to, inter alia, methods and apparatus for flexibly providing control data within large data structures.
2. Description of Related Technology
DisplayPort (see, inter alia, www.DisplayPort.org) is an exemplary digital display interface technology specified by the Video Electronics Standards Association (VESA). Extant DisplayPort technology is an extensible digital interface solution that is designed for a wide variety of performance requirements, and broadly supports devices such as PCs, monitors, panels, projectors, and high definition (HD) content applications. Current incarnations of the standard specify support for simple networking of digital audio/visual (A/V) interconnects, intended to be used primarily between an arbitrary assembly of multimedia “sources” (e.g., computers or CPUs) and “sinks” (e.g. display monitors, home-theater system, etc.).
DisplayPort provides, inter alia, unidirectional transmission of audio and video data from source nodes to sink nodes, and an auxiliary channel (back-channel) for capability and status information to be sent from the sink(s) to the source. The primary and auxiliary channels operate in “master/slave” mode under control of the master node. The master node controls both the low level transmission of data between source and sink, and the higher level management of the display and networking. Generally, the source node is the master node; however, it is appreciated that these functions (data source and network master) are logically separate and other network configurations may have different configurations, e.g., a sink node could be a master node.
The typical DisplayPort connection includes multiple data lanes (e.g. 1, 2, or 4 data pairs), and an embedded clock. Unlike other standards (e.g., HDMI, DVI), DisplayPort embeds the clock in the data signal transmission, and requires clock regeneration at the receiver. Audio signals may be optionally included, but are not required. The bi-directional auxiliary channel carries management and device control data. The data transmission protocol in DisplayPort is based on micro-packets which may be transmitted isochronously.
Existing DisplayPort symbols are based on 8B/10B encoding (i.e., ten (10) bits are used to represent an eight (8) bit data or control symbol). This represents a signaling overhead of approximately twenty percent (20%) (i.e., the number of information bits conveyed divided by the number of bits actually transmitted). For reasons explained in greater detail herein, other bus technologies provide much lower signaling overhead (e.g., 128B/130B, 128B/132B, etc.), but cannot support isochronous data applications (e.g., streaming video and audio, etc.). Ideally, improvements to the DisplayPort encoding scheme should seek to improve signaling overhead, while still supporting isochronous data applications. More generally, improved methods are needed for enabling flexible provision of control data within large data structures.